Method of making a double flanged timing belt pulley

ABSTRACT

A method of manufacturing a timing belt pulley of integral construction having side flanges on both sides with notched portions in each flange arranged alternately opposite non-notched portions in the other flange comprising the casting of the pulley using a suitable set of dies.

United States Patent 11 1 1111 3,91 Shiina 1*Nov. 11, 1975 [54] METHOD OF MAKING A DOUBLE 2.397,312 3/1946 Forrest 74/231 c FLANGED TIMING BELT PULLEY 2,902,234 9/1959 Morin 425/DlG. 34

2,958,904 11/1960 Morin 1 425/D|G1 34 Inventor: Toshlo ii y J p 3,461,946 8/1969 Nyselius 164/113 Assignee: Ricoh Co, Ltd. y Japan 3.807.747 4/1974 Shnna 74/230,05

[ Notice: The pOl'tiOn Of the term Of this patent subsequent to Aug. 13, 1991,

has been disclaimed' 1,171,295 11/1969 United Kingdom 164/1 19 [22] Filed: June 6, 1973 Primary E.\'aminer-Francis S. Husar [21] Appl' 367,443 Assistant E.\'aminer-John E. .Roethel Related U-S- ppli i n Data Attorney, Agent, or Firm-Cooper, Dunham, Clark, [63] Continuation-in-part 6f Ser. NO. 209650. Dec. 20, Griffin & Moran 1971, Pat. No. 3,807,247.

[30] Foreign Application Priority Data Dec. 28, 1970 Japan 45-119414 [57] ABSTRACT [52] US. Cl 164/137; 74/230.05 A method of manufacturing a timing belt pulley of in- [51] Int. Cl. B22D 33/04 tegral construction having side flanges on both sides [58] Field of Search 164/113, 119, 137; with notched portions in each flange arranged alter- 425/DIG. 34; 74/230.05, 231 C nately opposite non-notched portions in the other flange comprising the casting of the pulley using a [56] References Cited suitable set of dies.

UNITED STATES PATENTS 2,139,622 12/1938 Lonskey 74/230.05 3 Claims, 4 Drawing Figures Sheet 1 of 2 3,918,515

US. Patent Nov. 11, 1975 METHOD OF MAKING A DOUBLE FLANGED TIMING BELT PULLEY CROSS-REFERENCE This is a continuation-in-part application based on my co-pending application Ser. No. 209,650 filed on Dec. 20, 1971, and now US. Pat. No. 3,807,247, with claim of priority based on Japanese patent application Ser. No. ll9414/70, filed On Dec. 28, 1970.

BACKGROUND OF THE INVENTION The present invention relates a manufacturing method for a timing belt pulley formed as an integral part or casting andprovided with flanges on both sides.

In prior art timing belt pulleys of this type, the pulley and both flanges are manufactured as separate bodies and the flanges are pushed or cross-fitted into a hub portion provided on both sides of the pulley body or are calked therein. Because of this, these timing belt pulleys have a number of drawbacks, such as for example, the need for many parts and the push-in or calk process is complicated and these processes are unreliable. Ac-

cordingly, this has resulted in a high cost of the manufactured products.

The object of this invention is to obviate the abovementioned drawbacks of the conventional timing belt pulley by providing an integrally formed pulley casting.

BRIEF DESCRIPTION OF THE DRAWINGS dies of the present invention.

DETAILED DESCRIPTION OF THE INVENTION In FIGS. 1 and 2, a-pulley body 1 with side flanges 2 and 3 is shown formed as an integral part. In this case, both flanges 2 and 3 have notched portions arranged in substantially equal intervals and between these notched portions, each fan-shaped flange portion 2A and 3A, respectively, is positioned. The flange portions 2A and 3A are thus arranged alternately and the flange portion 2A of the flange 2 and the notched portion of the flange 3, and the notched portion ofthe flange 2 and the flange portion 3A of the flange 3, are respectively arranged oppositely. The widths in the circumferential direction of the notched portions are, as seen in FIG. 2, a little wider than the corresponding widths of the flange portions oppositely arranged.

As the timing belt pulley according to the present invention has the construction as mentioned above, the

timing belt pulley 1 and both flanges 2 and 3 may be formed as an integral part by using a suitable set of dies. Accordingly, it becomes unnecessary to push in the flanges or calk the flanges at a later time. A set of dies for this purpose is shown in FIG. 3 comprising a male die 4, having an end wall 4a, blank walls 4b, 4c, 4d, and a cylindrical mandrel 4e, and] a female die 5 with end wall 5a and blank walls 5b, 5c, 5d. When mated the pulley flanges are formed in the spaces allowed between the respective end walls and the end faces of the blank walls. The cogged hub portion is formed in the cavity occuring about the periphery of the mandrel 42. The molding material may be poured or injected at any point along the outer edge of the flange-forming spaces.

At the time of forming, if the joints of male die 4 and female die 5, for example such as the joint occuring between the abutting side faces of blank walls 4c and 5c, are arranged with their inner edges in the bottom portions of various cogs of the pulley itself, any adverse effect by a barrier formed in the: joint, for example, damage to a belt, can be avoided. It is preferred that the cutting depth of the cogs be larger than that of the conventional cogs so that a timing belt is not damaged even if a barrier is formed in the bottom portions of the cogs at the time of forming. Although in the drawings, there is shown an example wherein both flanges are divided into three flange portions, the present invention is not limited to this. The flange portions, in many cases, may be divided in accordance with the number of cogs of a pulley per se but it is not always necessary to do so. In a particular case the flanges may not be suitably divided equally depending upon the number of cogs needed and in this case the flanges may be divided in approximately equal portions. Also, the dies, which are shown as integral parts in FIG. 3, may be respectively constructed from a number of separate pieces 4a-4'e and 5a5'd as shown in FIG. 4.

As mentioned above, since the timing pulley of the present invention may be formed as an integral part or casting, the combination of the both flanges and the pulley per se is reliable. Therefore the present invention has a characteristic that the manufacturing cost becomes low.

What is claimed is:

l. A method of making a timing belt pulley having a hub portion with cogs thereon and side flanges integral with the hub portion, comprising the steps of assembling male and female dies with connecting cavities therebetween forminga cogged hub portion and side flanges with notches therein, the notches in each side flange being positioned opposite from non-notched portions of the opposite side flange, and in which each notch in each side flange extends circumferentially a distance at least as great as the circumferential extent of the non-notched portion of the opposite side flange, and filling the cavities with a casting material to form an integral timing belt pulley.

2. A method according to claim 1 wherein the cavities are formed such that a joint between the dies is located adjacent the bottom portion of a cog of the pulley.

3. A method according to claim 2 in which cavities are formed such that the depth of the cogs is made greater than the depth of the corresponding cogs on a belt adapted to engage the pulley. 

1. A method of making a timing belt pulley having a hub portion with cogs thereon and side flanges integral with the hub portion, comprising the steps of assembling male and female dies with connecting cavities therebetween forming a cogged hub portion and side flanges with notches therein, the notches in each side flange being positioned opposite from non-notched portions of the opposite side flange, and in which each notch in each side flange extends circumferentially a distance at least as great as the circumferential extent of the non-notched portion of the opposite side flange, and filling the cavities with a casting material to form an integral timing belt pulley.
 2. A method according to claim 1 wherein the cavities are formed such that a joint between the dies is located adjacent the bottom portion of a cog of the pulley.
 3. A method according to claim 2 in which cavities are formed such that the depth of the cogs is made greater than the depth of the corresponding cogs on a belt adapted to engage the pulley. 